Display device

ABSTRACT

A display panel includes a plurality of first pixels disposed in a first area, a plurality of second pixels disposed in a second area surrounded by the first area, a first touch sensing portion disposed in the first area, and a second touch sensing portion disposed in the second area with a density lower than the first ouch sensing portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit Republic of Korea PatentApplication No. 10-2020-0126266, filed on Sep. 28, 2020 in the KoreanIntellectual Property Office, the disclosure of which is incorporatedherein by reference in its entirety.

BACKGROUND Technical Field

The present disclosure relates to display devices.

Discussion of the Related Art

Image display devices configured to display various information or dataon a display screen act as a core device in the information andcommunication era. The display devices become thinner and lighter andare being developed to have high performance while being portable.Various needs for display devices for displaying an image haveincreased, and recently, various types of display devices, such as aLiquid Crystal Display (LCD) device, an Electroluminescence Display(ELD) device including a Quantum-dot Light Emitting Display deviceincluding a quantum dot (QD), an Inorganic Light Emitting Displaydevice, and an Organic Light Emitting Display device, and the like. havebeen developed and utilized.

Further, display devices are equipped with an input unit using a touchsensor or the like and an optical unit such as a camera, a proximitysensor, or the like in order to provide a user with more diverseapplication functions. However, due to the attachment of the opticalunit to the display devices, there is a problem that the design of thedisplay devices becomes difficult. In particular, since the camera andthe proximity sensor are required to be exposed to the outside for theentrance and exit of light, there is a problem in that an active area ofthe display panel is inevitably reduced.

Accordingly, in some cases, a display device has been designed to have alarge bezel for installation and exposure of an optical unit, allow aportion of an associated display panel to be cut out in a notch shape,or allow the optical unit to be exposed through a hole-shape portionformed in the active area. However, because a size of a display screenis still limited due to the camera, it is not easy to implement afull-screen display in actual.

SUMMARY

To implement a full-screen display, there is proposed a scheme ofassigning an imaging area, in which low-resolution pixels are disposed,in a screen of a display panel and arranging a camera and/or varioussensors in a position or region opposite to the imaging area under thedisplay panel. However, since the pixels are disposed in the imagingarea, there is a problem in that light transmittance of is lowered, andthe performance of the camera and/or such sensors is deteriorated. Ifsome elements normally required to be disposed in the imaging area areomitted or reduced to address such an issue, performance related to suchelements may be deteriorated. To address these issues, embodimentsdescribed herein provide a display device that enables light toeffectively transmit toward an optical unit without the deterioration ofcorresponding basic performance. Issues or problems for solving in thepresent disclosure are not limited thereto, and other issues or problemswill become apparent to those skilled in the art from the followingdescription.

Accordingly, embodiments of the present disclosure are directed to adisplay device that substantially obviates one or more of the problemsdue to limitations and disadvantages of the related art.

Features and aspects will be set forth in the description that follows,and in part will be apparent from the description, or may be learned bypractice of the inventive concepts provided herein. Other features andaspects of the inventive concepts may be realized and attained by thestructure particularly pointed out in the written description, orderivable therefrom, and the claims hereof as well as the appendeddrawings.

To achieve these and other aspects of the inventive concepts, asembodied and broadly described, a display panel is provided. The displaypanel includes a plurality of first pixels disposed in a first area, aplurality of second pixels disposed in a second area surrounded by thefirst area, a first touch sensing portion disposed in the first area,and a second touch sensing portion disposed in the second area with adensity lower than the first touch sensing portion. The first and secondtouch sensing portions are based on a mutual-capacitive sensing scheme,and corresponding capacitances caused by respective touch inputs intothe first and second areas may be substantially equal. The second areamay overlap a camera module or unit, and a density of the second pixelsdisposed in the second area may be lower than that of the first pixelsdisposed in the first area. The second area may include alight-transmitting area disposed between the second pixels, and thesecond touch sensing portion may not be disposed in thelight-transmitting area.

An encapsulation layer may be disposed on or over the first and secondpixels, and the first and second touch sensing portions may be disposedon an upper surface of the encapsulation layer.

The first and second touch sensing portions respectively may includefirst and second touch electrodes having a line shape, and a width ofthe line-shaped second touch electrode may be larger than that of theline-shaped first touch electrode. For example, a width of theline-shaped second touch electrode may be 1.2 to 2 times larger thanthat of the line-shaped first touch electrode. In another example, awidth of the line-shaped second touch electrode may be 3 um to 24 um.

The line-shaped second touch electrode may include a first portionhaving a first width and a second portion having a second width largerthan the first width.

The first touch sensing portion may be located on or over a bank locatedbetween the first pixels, and the second touch sensing portion may belocated on or over a bank located between the second pixels.

Various specific features, configurations, techniques and processes areincluded in detailed description and the accompanying drawings, and willbe discussed in detail below.

In accordance with aspects of the present disclosure, it is possible toprovide a display device equipped with an optical unit or module withouta decrease in a display area of a display panel. Further, in accordancewith aspects of the present disclosure, it is possible to provide adisplay device capable of preventing the deterioration of touch sensingperformance while improving light transmittance in an imaging area. Inaccordance with aspects of the present disclosure, it is possible toprovide a display device having improved aesthetics and functionality.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the inventive concepts asclaimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this application, illustrate embodiments of the disclosure andtogether with the description serve to explain various principles. Inthe drawings:

FIG. 1 illustrates schematically a display device according to aspectsof the present disclosure.

FIG. 2 is a cross-sectional view illustrating schematically a displaypanel and an optical sensor included in the display device according toaspects of the present disclosure.

FIG. 3 illustrates pixels disposed in a display area of a display panelaccording to aspects of the present disclosure.

FIG. 4 illustrates pixels in an imaging area, and a light-transmittingarea according to aspects of the present disclosure.

FIG. 5 is an enlarged view for portion A of FIG. 4.

FIG. 6 illustrates a touch sensing portion according to aspects of thepresent disclosure.

FIG. 7 is a cross-sectional view illustrating the touch sensing portionof FIG. 6.

FIGS. 8A and 8B illustrate a touch sensing portion in a display areaaccording to aspects of the present disclosure.

FIGS. 9A and 9B illustrate a touch sensing portion in an imaging areaaccording to aspects of the present disclosure.

FIG. 10 illustrates touch electrodes according to aspects of the presentdisclosure.

DETAILED DESCRIPTION

The advantages and features of the present disclosure and methods ofachieving the same will be apparent by referring to embodiments of thepresent disclosure as described below in detail in conjunction with theaccompanying drawings. However, the present disclosure is not limited tothe embodiments set forth below, but may be implemented in variousdifferent forms. The following embodiments are provided only tocompletely disclose the present disclosure and inform those skilled inthe art of the scope of the present disclosure, and the presentdisclosure is defined only by the scope of the appended claims.

In addition, the shapes, sizes, ratios, angles, numbers, and the likeillustrated in the accompanying drawings for describing the exemplaryembodiments of the present disclosure are merely examples, and thepresent disclosure is not limited thereto. Like reference numeralsgenerally denote like elements throughout the present specification.Further, in the following description of the present disclosure,detailed description of well-known functions and configurationsincorporated herein will be omitted when it is determined that thedescription may make the subject matter in some embodiments of thepresent disclosure rather unclear. The terms such as “including”,“having”, “containing”, “comprising of”, and “consist of” used hereinare generally intended to allow other components to be added unless theterms are used with the term “only”. Singular forms used herein areintended to include plural forms unless the context clearly indicatesotherwise. In interpreting any elements or features of the embodimentsof the present disclosure, it should be considered that any dimensionsand relative sizes of layers, areas and regions include a tolerance orerror range even when a specific description is not conducted.

Spatially relative terms, such as, “on”, “over”, “above”, “below”,“under”, “beneath”, “lower”, “upper”, “near”, “close”, “adjacent”, andthe like, may be used herein to describe one element or feature'srelationship to another element(s) or feature(s) as illustrated in thefigures, and it should be interpreted that one or more elements may befurther “interposed” between the elements unless the terms such as“directly”, “only” are used. A location, arrangement, or disposition ofa first element or layer “on” a second element or layer may include thatnot only is the first element or layer located, arranged, or disposeddirectly on the second element or layer, but a third element or layer isinterposed between the first element or layer and the second element orlayer. Herein, situations in which two or more elements included inembodiments of the present disclosure are connected, combined, coupled,contacted, or the like may include not only directly or physicallyconnecting, combining, coupling, or contacting between two or moreelements, but interposing of another element between the two or moreelements.

When the terms, such as “first”, “second”, or the like, are used hereinto describe various elements or components, it should be considered thatthese elements or components are not limited thereto. These terms aremerely used herein for distinguishing an element from other elements.Therefore, a first element mentioned below may be a second element in atechnical concept of the present disclosure.

The size and thickness of each component shown in the drawings areillustrated for convenience of description, and thus, embodiments of thepresent disclosure are not necessarily limited thereto. Hereinafter,with reference to the accompanying drawings, various embodiments of thepresent disclosure will be described in detail.

FIG. 1 illustrates schematically a display device according to aspectsof the present disclosure. FIG. 2 is a cross-sectional view illustratingschematically a display panel and an optical sensor included in thedisplay device. FIG. 3 illustrates pixels disposed in a display area ofthe display panel.

Referring to FIG. 1, the entirety of a surface of the display device100, or most of the surface, may serve as a display area. The displayarea may include a first area DA and a second area CA. In this instance,both the first area DA and the second area CA can present images, butmay have different resolutions from each other. For example, theresolution of multiple second pixels disposed in the second area CA maybe lower than the resolution of multiple first pixels disposed in thefirst area DA. A sufficient amount of light corresponding to a degree towhich the resolution of multiple second pixels disposed in the secondarea CA is lowered can be allowed to enter one or more sensors (41, 42)disposed in the second area CA. However, embodiments of the presentdisclosure are not limited thereto. For example, if the second area CAhas sufficient light transmittance, or an algorithm suitable for noisecompensation is implemented, the resolution of the second area CA may besubstantially equal to the resolution of the first area DA.

The second area CA may be an area in which one or more sensors (41, 42)are disposed. The second area CA is an area overlapping one or moresensors; therefore, may have an area smaller than the first area DA inwhich most images are present. Each sensor (41, 42) may include at leastone of an image sensor, a proximity sensor, an illuminance sensor, agesture sensor, a motion sensor, a fingerprint recognition sensor, and abiometric sensor. For example, a first sensor 41 may be an illuminancesensor, and a second sensor 42 may be an image sensor for detectingstill images or moving images; however, embodiments of the presentdisclosure are not limited thereto.

The second area CA may be placed at a location where the entrance oflight is required. For example, the second area CA may be placed in anupper left portion or upper right portion of a display area, or placedacross the entirety of an upper portion of the display area or most ofthe upper portion. In these situations, respective widths of theseportions may be variously changed according to desired requirements.However, embodiments described herein are not limited thereto. Forexample, the second area CA may be placed in a central portion or lowerportion of the display area. Hereinafter, the first area DA may bereferred to as a display area, and the second area CA may be referred toas an imaging area.

The display area DA and the imaging area CA each may include one or morepixel arrays in which pixels to which pixel data are loaded arearranged. The number of pixels per unit area (e.g., Pixels Per Inch,PPI) of the imaging area CA may be lower than the PPI of the displayarea DA in order to ensure sufficient light transmittance.

Since both the display area DA and the imaging area CA include pixels,input images can be reproduced on the display area DA and the imagingarea CA. Each of pixels in the display area DA and the imaging area CAmay include sub-pixels having different colors to implement images withcolors. Each sub-pixel may be one of a red sub-pixel (hereinafter,referred to as “R sub-pixel”), a green sub-pixel (hereinafter, referredto as “G sub-pixel”), and a blue sub-pixel (hereinafter, referred to as“B sub-pixel”). Although not shown, each pixel P may further include awhite sub-pixel (hereinafter, referred to as “W sub-pixel”). Eachsub-pixel may include a pixel circuit and a light emitting element, suchas a light emitting diode including an organic light emitting diode(OLED).

The display panel has a width in the X-axis direction, a length in theY-axis direction, and a thickness in the Z-axis direction. The displaypanel may include a circuit layer 12 disposed on or over a substrate 10and a light emitting element layer 14 disposed on or over the circuitlayer 12. A polarizing layer 18 may be disposed on or over the lightemitting element layer 14, and a cover glass 20 may be disposed on orover the polarizing layer 18.

The circuit layer 12 may include lines such as data lines, gate lines,and power lines, a pixel circuit connected to such lines, a gate driverconnected to the gate lines, and the like. The circuit layer 12 mayinclude circuit elements such as at least one transistor implemented asa Thin Film Transistor (TFT), a capacitor, and the like. The lines andcircuit elements of the circuit layer 12 may be implemented or disposedin or through a plurality of insulating layers, two or more metal layersseparated by an insulating layer therebetween, and an active layerincluding a semiconductor material.

The light emitting element layer 14 may include a light emitting elementdriven by the pixel circuit, for example, a light emitting diodeincluding an organic light emitting diode (OLED), or the like. The lightemitting element may be implemented as the organic light emitting diode(OLED). The OLED may include an organic material layer formed between ananode and a cathode. The organic material layer may include a holeinjection layer (HIL), a hole transport layer (HTL), an emission layer(EML), an electron transport layer (ETL), and an electron injectionlayer (EIL); however, embodiments of the present disclosure are notlimited thereto. When voltages are applied to the anode and cathode ofthe OLED, holes passing through the hole transport layer (HTL) andelectrons passing through the electron transport layer (ETL) can move tothe emission layer (EML), and then form excitons. Thereby, visible lightcan be emitted from the emission layer (EML). The light emitting elementlayer 14 may be disposed on or over pixels that selectively transmitrespective wavelengths of red light, green light, and blue light, andfurther include a color filter array.

The light emitting element layer 14 may be covered by an encapsulationlayer. The encapsulation layer may have a structure in which an organicfilm and an inorganic film are alternately stacked. In this instance,the inorganic film may serve to block the penetration of moisture oroxygen, and the organic film may serve to flatten a surface of theinorganic film. In the structure having the multilayer stacked with theorganic film and the inorganic film, a path through which moisture oroxygen travels may become longer than that in a structure having asingle layer, and therefore, the penetration of moisture/oxygenaffecting the light emitting element layer 14 can be effectivelyprevented.

The polarizing layer 18 may be bonded on the light emitting elementlayer 14 or the encapsulation layer. The polarizing layer 18 can serveto improve outdoor visibility of the display device. The polarizinglayer 18 can serve to reduce light reflected from the surface of thedisplay panel and block light reflected from the metal of the circuitlayer 12 to improve brightness of pixels. The polarizing layer 18 may beimplemented as a linear polarizing plate 18, a polarizing plate 18 onwhich a phase delay film is bonded, or a circular polarizing plate 18.

The display device 100 according to aspects of the present disclosuremay include an optical sensor disposed under a display screen. Theoptical sensor can capture external images in a capture mode and supplyphotographic or moving image data. The optical sensor may correspond to,and be located under, the imaging area CA. In this situation, a lens 30of the optical sensor may face the imaging area CA. The external lightmay enter the lens of the optical sensor through the imaging area CA,and the lens 30 may condense the light to the image sensor. Meanwhile,in a situation where the resolution of the imaging area CA is reduced toensure light transmittance, an image quality compensation algorithm maybe applied for compensating for the luminance and color coordinates ofpixels in the imaging area CA.

According to embodiments described herein, as pixels are also disposedin the imaging area CA, a full-screen display can be implemented withoutlimitation in the display area due to an optical sensor.

As illustrated in FIG. 3, the display area DA may include pixelsarranged in a matrix pattern. Each of the pixels may be implemented as areal-type pixel including R, G, and B sub-pixels of three primarycolors, which make up one pixel. Each of the pixels may further includea W sub-pixel omitted in the drawing. Further, two sub-pixels may makeup one pixel using a sub-pixel rendering algorithm. For example, a firstpixel PIX1 may be made up of R and G sub-pixels, and a second pixel PIX2may be made up of B and G sub-pixels. Insufficient color representationin each of the pixels PIX1 and PIX2 may be compensated for by an averagevalue of corresponding color data between neighboring pixels.

FIG. 4 illustrates an imaging area according to aspects of the presentdisclosure. FIG. 5 is an enlarged view for portion A of FIG. 4.

Referring to FIGS. 4 and 5, the imaging area CA may include one or morepixel groups PG, each of which includes one or more pixels, spaced apartby a predetermined distance D1 from one another, and one or morelight-transmitting areas AG disposed between neighboring pixel groupsPG. The light-transmitting area AG may be disposed between pixels. Inthis manner, more sufficient external light can enter the lens of theoptical sensor through the light-transmitting area AG. A shape of thelight-transmitting area AG is illustrated in a circular shape; however,embodiments of the present disclosure are not limited thereto. Forexample, the light-transmitting area AG may be designed in variousshapes such as a circle, an ellipse, a polygon, and the like.

The light-transmitting area AG may include one or more transparentmaterials having high light transmittance for enabling light to enterthe light-transmitting area AG such that a loss of the incident light isminimized. For example, the light-transmitting area AG may includetransparent insulating materials without including metal lines orpixels. In this instance, the lines TS of the pixels may be disposedoutside of the light-transmitting area AG. However, embodimentsdescribed herein are not limited thereto; for example, a metal electrodematerial may remain in a partial area in the light-transmitting area AG.In this manner, the amount of light incident on the sensor through thelight-transmitting area may increase, and the light transmittance of theimaging area CA may increase as the light-transmitting area AGincreases.

Each pixel group PG may include one or two pixels. Further, each of thepixels may include two to four sub-pixels. For example, each pixel ineach pixel group may include all of the R, G, and B sub-pixels, or mayinclude two of the R, G, and B sub-pixels. According to implementations,each pixel may further include W sub-pixel.

A distance D3 between the light-transmitting areas AG may be smallerthan a distance (e.g., a pitch) D1 between the pixel groups PG. Adistance D2 between the sub-pixels may be smaller than the distance D1between the pixel groups PG.

FIG. 6 illustrates a touch sensing portion according to aspects of thepresent disclosure. FIG. 7 is a cross-sectional view illustrating thetouch sensing portion of FIG. 6.

The display device 100 according to aspects of the present disclosuremay include the touch sensing portion TS capable of sensing a touchinput performed on an associated display panel. In particular, the touchsensing portion TS included in the display device 100 may be disposedtaking account of an imaging area CA located in a display area DA of thedisplay panel. The touch sensing portion TS may include one or moretouch electrodes TE, one or more bridges BR, one or more routing lines,and the like. The touch electrode TE may be a surface electrode, a lineelectrode, and/or a mixture thereof. When the touch electrode TE is theline electrode, the sensing portion may have a mesh pattern in which aplurality of touch electrodes are arranged in the mesh pattern.

In one embodiment, when the touch sensing portion TS is based on themutual-capacitive sensing scheme, the touch electrodes TE are dividedinto one or more driving electrodes Tx and one or more sensingelectrodes Rx. The driving electrode Tx may have a plurality ofchannels, and each channel may be routed on a channel basis in anon-pixel area. The sensing electrode Rx may have a plurality ofchannels, and each channel may be routed one a channel basis in thenon-pixel area. The bridge BR may be formed in an area where eachdriving electrode Tx and each sensing electrode Rx intersect.

The touch sensing portion TS may be provided as a separate panel or maybe directly disposed on an encapsulation layer 16. In anotherembodiment, a touch buffer layer 171 may be disposed on theencapsulation layer 16, and the touch electrode TE and the bridge BR maybe disposed on or over the touch buffer layer 171. The touch bufferlayer 171 may be formed of an inorganic insulating material. The touchelectrode TE may be made up of a single layer or multiple layersincluding a metal having high corrosion resistance and acid resistanceand good conductivity, such as aluminum (Al), titanium (Ti), copper(Cu), molybdenum (Mo), and the like. A touch passivation film 172 may bedisposed on the touch electrode TE. The touch passivation film 172 maybe formed of an organic insulating material or an inorganic insulatingmaterial.

One or more touch electrodes TE may also be disposed in the imaging areaCA. If touch electrodes TE are not disposed in the imaging area CA, aproblem in forming mutual capacitance may occur, and as a result, theaccuracy of touch sensing may be reduced in that portion. In contrast,if touch electrodes TE are densely disposed in the imaging area CA, theaccuracy of touch sensing may be increased, but an amount of lightincident to the optical sensor 30 may be reduced. In the display deviceaccording to aspects of the present disclosure, as shown in FIG. 7, adistance (e.g., a pitch) between touch electrodes TE in the imaging areaCA may be relatively smaller than that between touch electrodes TE inthe display area DA. For example, a pitch between the touch electrodesTE in the imaging area CA may be two times smaller than a pitch betweenthe touch electrodes TE in the display area DA.

FIGS. 8A and 8B illustrate a touch sensing portion in a display area ofthe display panel according to aspects of the present disclosure. FIGS.9A and 9B illustrate a touch sensing portion in an imaging area of thedisplay panel according to aspects of the present disclosure.

The display device according to aspects of the present disclosure mayinclude one or more touch sensing portions that are disposed in variouspatterns. That is, the display device may include one or more touchsensing portions disposed taking account of characteristics of severalportions of the display area.

In one embodiment, the display panel may include a first touch sensingportion disposed in a first area (e.g., display area DA), and a secondtouch sensing portion disposed in a second area (e.g., imaging area CA)with a density (or pitch) lower (or smaller) than the first touchsensing portion. In this situation, one or more first pixels aredisposed in the first area DA, and one or more second pixels aredisposed in the second area CA surrounded by the first area DA. In oneembodiment, in the same manner as respective densities of the firsttouch sensing portion in the first area and the second touch sensingportion in the second area, a density of the second pixels disposed inthe second area CA may be lower than that of the first pixels disposedin the first area DA. In this arrangement, since the second area CA hasa higher light transmittance than the first area DA, an optical sensor(e.g., a camera module) may overlap (correspond to) the second area CA.

Cross-sectional structures of the display panel according to embodimentsdescribed herein are shown in FIGS. 8b and/or 9 b. However, structuresof the display panel according to embodiments described herein are notlimited thereto. The display panel may have a structure in which acircuit layer 12, a light emitting element layer 14, an encapsulationlayer 16, a touch sensing portion, a polarizing layer 18, a cover layer20, and the like are stacked on or over a substrate 10. The substrate 10may include a first PI substrate, a second PI substrate, and aninorganic film (IPD) disposed therebetween. The inorganic film IPD canblock the penetration of moisture from a lower portion of the secondsubstrate.

The circuit layer 12 may include lines such as data lines, gate lines,and power lines, a pixel circuit connected to such lines, a gate driverconnected to the gate lines, and the like. The circuit layer 12 mayinclude circuit elements such at least one transistor implemented as athin film transistor (TFT), a capacitor, and the like. The lines andcircuit elements of the circuit layer 12 may be implemented with,disposed in, or including, a plurality of insulating layers, a metallayer separated by an insulating layer therebetween, and/or an activelayer including a semiconductor material. An upper portion of thecircuit layer 12 may be covered with a planarization layer. A circuitelement (e.g., TFT) and a light emitting element (e.g., OLDE) of thelight emitting element layer may be connected through a hole formed inthe planarization layer.

The light emitting element layer 14 may include the light emittingelement (e.g., OLDE) driven by the pixel circuit. The light emittingelement may include an anode electrode, a cathode electrode 146, and anorganic material layer 144 disposed between the anode and cathodeelectrodes. The anode electrode of the light emitting element may bedisposed on or over the planarization layer. The anode electrode mayinclude a transparent or translucent electrode material. The anodeelectrode may be connected to an electrode of a TFT used as a switchelement or a driving element through a contact hole formed in theplanarization layer. The anode electrode is formed (patterned) for eachsub-pixel.

A portion except for a light emitting area in the upper portion of theanode electrode is covered with a bank 148. At this situation, the bank148 may cover at least a portion of the anode electrode. However, whendesired, as shown in FIG. 9B, the bank 148 may not be disposed in anarea where the light emitting element is not disposed. This structuremay be implemented to further improve the light transmittance of thelight-transmitting area AG.

As described above, the bank 148 may be a pattern of defining a lightemitting area (or an opening area) and function as a pixel defininglayer for defining a boundary between pixels. A spacer may be formed onthe bank 148. The spacer can allow a gap between a fine metal mask (FMM)and the anode electrode to be formed so that the FMM cannot contact theanode electrode during a deposition process of an organic material 144.The bank 148 and the spacer may be integrated with the same organicinsulating material.

An organic material layer 144 may be disposed in a light emitting areaof each pixel defined by the bank. The cathode electrode 146 that is asecond electrode of the light emitting element OLED may be disposed inall or at least a portion of a surface of the display panel to cover thebank, the spacer, and the organic material layer 144. The cathodeelectrode 146 may be connected to a base power supply (VSS) line formedin any one of metal layers under the cathode electrode 146.

A capping layer may cover the cathode electrode 146. As the cappinglayer of an inorganic insulating material covers the cathode electrode146, the capping layer can protect the cathode electrode 146 by blockingthe penetration of air and out-gassing of an organic insulating materialapplied on the capping layer.

The encapsulation layer 16 may be located on or over the cathodeelectrode or the capping layer. The encapsulation layer 16 may have astructure in which a first inorganic film 161, an organic film 162, anda second inorganic film 163 are sequentially stacked. In this instance,the first inorganic film 161 may cover the capping layer, and theorganic film 162 may be disposed on the first inorganic film 161. Theorganic film 162 may include an organic insulating material. The secondinorganic film 163 may be disposed on the organic film 162.

The polarization layer 18 may be disposed on the encapsulation layer 16and can improve outdoor visibility of the display device. The polarizinglayer 18 can serve to reduce light reflected from a surface of thedisplay panel and block light reflected from the metal of the circuitlayer 12 to improve brightness of pixels.

The touch sensing portion applied to the display device according toembodiments described herein may be integrated with the display panel.In one embodiment, the display panel may further include anencapsulation layer 16 on or over the first pixels and the secondpixels, and the first and second touch sensing portions may be disposedon or over an upper surface of the encapsulation layer 16. That is, asshown in FIG. 8B, a first touch electrode TE1 included in the firsttouch sensing portion may be directly disposed on the upper surface ofthe encapsulation layer 16. Likewise, as shown in FIG. 9B, a secondtouch electrode TE2 included in the second touch sensing portion may bedirectly disposed on the upper surface of the encapsulation layer 16. Inthis instance, the first touch electrode TE1 and the second touchelectrode TE2 may be disposed on the buffer layer 171 for insulationand/or enhanced adhesive strength. A touch protection film 172 formed ofan organic insulating material or an inorganic insulating material maycover the first touch electrode TE1 and the second touch electrode TE2.

A structure of the display panel in a plan view according to embodimentsdescribed herein is shown in FIGS. 8A and/or 9A. However, the displaypanel according to embodiments described herein are not limited thereto.Touch sensing portions included in the display panel or respectiveelements included in the touch sensing portions may differently arrangedin respective areas. That is, touch sensing portions included in thedisplay panel, or respective elements included in the touch sensingportions may be differently disposed in the display area DA and theimaging area CA, respectively.

As described above, since the imaging area CA is required to providemaximal incident light to an optical sensor under the substrate, anarrangement density of either touch sensing portion in the imaging areaCA or elements included in touch sensing portion may be reduced comparedto that in the display area DA. That is, a distance between touchelectrodes included in the touch sensing portion of the imaging area CAmay be designed to be longer than a distance between touch electrodesincluded in display area DA. Inventors of the present disclosurerecognized a problem in which although the transmittance of the imagingarea may be ensured through such different arrangements, a capacitancebetween touch electrodes reduces due to a trade-off, and the performanceof corresponding touch sensing deteriorates. To address this issue, theinventors invented a structure for uniformly ensuring touch sensingperformance while improving the transmittance of the imaging area. Sucha structure may be implemented by differently designing shapes of touchelectrodes disposed in the display area DA and the imaging area CA.

In one embodiment, a first touch sensing portion disposed in the firstarea DA and a second touch sensing portion disposed in the second areaCA are based on the mutual-capacitive sensing scheme, and correspondingcapacitances caused by respective touch inputs into the first and secondareas DV and CA may be substantially equal.

Specifically, the first touch sensing portion disposed in the first areaDA and the second touch sensing portion disposed in the second area CArespectively may include one or more first touch electrodes TE1 and oneor more second touch electrodes TE2, which have a line shape, and awidth of the line-shaped second touch electrode TE2 may be larger thanthat of the line-shaped first touch electrode TE1. This is based on theprinciple that capacitance is proportional to the cross-sectional areaof an electrode and inversely proportional to a distance betweenelectrodes. This principle can be used to compensate for a reduction incapacitance as electrodes are spaced far apart from one another in thesecond area CA, by increasing cross-sectional areas of the electrodes.

A width W2 of the line-shaped second touch electrode TE2 may be 1.2 to 2times larger than a width W1 of the line-shaped first touch electrodeTE1. For example, a width of the line-shaped second touch electrode TE2may be 3 um to 24 um.

Specifically, the first touch electrodes TE1 and the second touchelectrode TE2 may be arranged in a mesh pattern in respective entireareas. The first touch sensing portion (e.g., one or more electrodes)may be located on or over a bank located between the first pixels, andthe second touch sensing portion (e.g., one or more electrodes) may belocated on or over a bank located between the second pixels. This is forpreventing the first touch sensing portion (e.g., one or moreelectrodes) and the second touch sensing portion (e.g., one or moreelectrodes) from blocking respective light emitting areas.

The second area CA may include a light-transmitting area disposedbetween the second pixels, and the light-transmitting area is an areaprovided to increase the light transmittance of the second area CA. Thesecond touch sensing portion may not be disposed in thelight-transmitting area. The cathode electrode 146 may include anopening corresponding to the light-transmitting area. Such an openingmay be formed, after disposing the cathode electrode 146 on the bank148, by etching the cathode electrode 146 and the bank 148 at one time;however, methods of forming the opening in the cathode electrode are notlimited to a specific method. For example, it is possible to form anopening in the cathode electrode, after the cathode electrode has beenformed, using an etching process, or a portion of the cathode electrodemay be removed by using an IR laser located under the substrate 10.

FIG. 10 illustrates touch electrodes according to aspects of the presentdisclosure.

As shown in FIG. 10, a line-shaped second touch electrode TE2 disposedin the imaging area CA may include a first portion having a first widthX, and a second portion having a second width 5X that is wider than thefirst width X. The first width X may be equal to or greater than a widthof a line-shaped first touch electrode TE1 disposed in the display areaDA. The second width 5X may have a width equal to or less than 5 timesthe first width X.

In the display device according to aspect of present disclosure, since asufficient amount of light is allowed to enter the optical sensorthrough the above-described configurations, image quality can beimproved, and noises of captured image data can be reduced. Further, inthe display device according to aspect of present disclosure, the touchsensing performance of the imaging area can be uniformly maintained.

The display device according to aspects of the present disclosure can bedescribed as follows. The display device includes a substrate having afirst surface and a second surface opposite to the first surface, aplurality of first light emitting elements disposed in a first area onthe first surface, a plurality of second light emitting elementsdisposed in a second area surrounded by the first area, a first touchsensing portion disposed in the first area, a second touch sensingportion disposed in the second area with a density lower than the firsttouch sensing portion, and an optical sensor disposed under the secondsurface of the substrate. The second area may include alight-transmitting area disposed between the second light emittingelements, and the second touch sensing portion may not be disposed inthe light-transmitting area. A density of the second light emittingelements disposed in the second area may be lower than that of the firstlight emitting elements disposed in the first area.

An encapsulation layer may be disposed on or over the first and secondlight emitting elements, and the first and second touch sensing portionsmay be disposed on an upper surface of the encapsulation layer. Thefirst touch sensing portion may be located on or over a bank locatedbetween the first light emitting elements, and the second touch sensingportion may be located on or over a bank located between the secondlight emitting elements.

The first and second touch sensing portions respectively may includefirst and second touch electrodes having a line shape, and a width ofthe line-shaped second touch electrode may be larger than that of theline-shaped first touch electrode. For example, a width of theline-shaped second touch electrode may be 1.2 to 2 times larger thanthat of the line-shaped first touch electrode. A width of theline-shaped second touch electrode may be 3 um to 24 um.

The line-shaped second touch electrode may include a first portionhaving a first width and a second portion having a second width largerthan the first width. The above description has been presented to enableany person skilled in the art to make and use the invention, and hasbeen provided in the context of a particular application and itsrequirements. Various modifications, additions and substitutions to thedescribed embodiments will be readily apparent to those skilled in theart, and the general principles defined herein may be applied to otherembodiments and applications without departing from the spirit and scopeof the present invention. Although the exemplary embodiments have beendescribed for illustrative purposes, a person skilled in the art willappreciate that various modifications and applications are possiblewithout departing from the essential characteristics of the presentdisclosure. For example, the specific components of the exemplaryembodiments may be variously modified. The elements or features ofvarious exemplary embodiments of the present disclosure can be partiallyor entirely bonded to or combined with each other and can be interlockedand operated in technically various ways as can be fully understood by aperson having ordinary skill in the art, and the various exemplaryembodiments can be carried out independently of or in association witheach other.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the display device of thepresent disclosure without departing from the technical idea or scope ofthe disclosure. Thus, it is intended that the present disclosure coverthe modifications and variations of this disclosure provided they comewithin the scope of the appended claims and their equivalents.

What is claimed is:
 1. A display panel comprising: a plurality of firstpixels disposed in a first area; a plurality of second pixels disposedin a second area surrounded by the first area; a first touch sensingportion disposed in the first area; and a second touch sensing portiondisposed in the second area with a density lower than the first touchsensing portion.
 2. The display panel according to claim 1, furthercomprising a camera module, wherein the second area overlaps the cameramodule, and wherein a density of the second pixels disposed in thesecond area is lower than a density of the first pixels disposed in thefirst area.
 3. The display panel according to claim 1, furthercomprising an encapsulation layer disposed on or over the first andsecond pixels, wherein the first and second touch sensing portions aredisposed on an upper surface of the encapsulation layer.
 4. The displaypanel according to claim 1, wherein the first and second touch sensingportions respectively include first and second touch electrodes having aline shape, and a width of the second touch electrode is larger than awidth of the first touch electrode.
 5. The display panel according toclaim 4, wherein a width of the second touch electrode is 3 um to 24 um.6. The display panel according to claim 4, wherein a width of the secondtouch electrode is 1.2 to 2 times larger than that of the first touchelectrode.
 7. The display panel according to claim 4, wherein the secondtouch electrode comprises: a first portion having a first width; and asecond portion having a second width greater than the first width. 8.The display panel according to claim 1, wherein the second area includesa light-transmitting area disposed between the second pixels, and thesecond touch sensing portion is not disposed in the light-transmittingarea.
 9. The display panel according to claim 1, wherein the first touchsensing portion is located on or over a bank located between the firstpixels, and the second touch sensing portion is located on or over abank located between the second pixels.
 10. The display panel accordingto claim 1, wherein the first and second touch sensing portions arebased on a mutual-capacitive sensing scheme, and capacitances caused byrespective touch inputs into the first and second areas aresubstantially equal.
 11. A display device comprising: a substrate havinga first surface and a second surface opposite to the first surface; aplurality of first light emitting elements disposed in a first area onthe first surface; a plurality of second light emitting elementsdisposed in a second area surrounded by the first area; a first touchsensing portion disposed in the first area; a second touch sensingportion disposed in the second area with a density lower than the firsttouch sensing portion; and an optical sensor disposed under the secondsurface of the substrate.
 12. The display device according to claim 11,wherein a density of the second light emitting elements disposed in thesecond area is lower than that of the first light emitting elementsdisposed in the first area.
 13. The display device according to claim11, further comprising an encapsulation layer disposed on or over thefirst and second light emitting elements, wherein the first and secondtouch sensing portions are disposed on an upper surface of theencapsulation layer.
 14. The display device according to claim 11,wherein the first and second touch sensing portions respectively includefirst and second touch electrodes having a line shape, and a width ofthe second touch electrode is larger than a width of the first touchelectrode.
 15. The display device according to claim 14, wherein a widthof the second touch electrode is 3 um to 24 um.
 16. The display deviceaccording to claim 14, wherein a width of the second touch electrode is1.2 to 2 times larger than that of the first touch electrode.
 17. Thedisplay device according to claim 14, wherein the second touch electrodecomprises: a first portion having a first width; and a second portionhaving a second width greater than the first width.
 18. The displaydevice according to claim 11, wherein the second area includes alight-transmitting area disposed between the second light emittingelements, and the second touch sensing portion is not disposed in thelight-transmitting area.
 19. The display device according to claim 11,wherein the first touch sensing portion is located on or over a banklocated between the first light emitting elements, and the second touchsensing portion is located on or over a bank located between the secondlight emitting elements.